1. Field of the Invention
This invention relates to a flavonoid glycoside exhibiting an excellent antiallergic effect even in a small amount.
2. Description of the Prior Art
Flavonoids are a class of compounds which are widely distributed in the plant kingdom and have been known from long ago. A flavonoid is a modulator for germination and growth of a seed, as well as is believed to absorb ultraviolet rays in sunlight to protect internal tissues. In particular, it is known that a flavonoid protects and strengthen capillary vessels in human body.
One aspect of the present invention relates to a product comprising a food, drug or cosmetic and a flavonoid glycoside represented by formula I wherein the flavonoid glycoside is present in an antiallergenic effective amount. 
Another aspect of the present invention provides a method of inhibiting histamine release by administering to a mammal an antiallergenic effective amount of a flavonoid glycoside represented by formula I.
Yet another aspect of the present invention provides a method of obtaining a flavonoid glycoside represented by formula I by extracting the flavonoid glycoside from a plant in the Cassia genus.